In the drive train of an automotive vehicle utilizing a manual transmission, a clutch assembly is interposed between the vehicle engine and the transmission, and a torsional vibration damper is conventionally utilized in the clutch assembly to neutralize any torsional vibrations emanating from the vehicle engine which would otherwise cause undesirable characteristics; e.g. impact loads, pulsations, noises, etc. in the transmission and driveline during operation of the vehicle.
Where an automatic transmission has a fluid coupling or hydraulic torque converter, the torsional vibrations in the system are effectively absorbed hydraulically and a vibration damper has been found unnecessary. However, in order to enhance the fuel economy of a vehicle equipped with an automatic transmission, a lock-up clutch may be incorporated into the fluid coupling or torque converter which, at a predetermined point that may relate to vehicle speed, load and acceleration, locks up to provide a direct drive between the fluid coupling input and output in high gear. When locked in direct drive, the torsional vibrations will not be hydraulically absorbed and a vibration damper may be required.
The present invention relates to an improved vibration damper assembly which provides for a relatively low rate, high amplitude deflection between the driving and driven members in a torsional coupling or clutch assembly. The assembly includes a hub having a pair of oppositely extending radial arms, a driving member having a pair of drive tangs cooperating with the hub arms, and a pair of floating equalizers journalled on the hub for rotation relative thereto. Damping springs are positioned between the hub arms and oppositely extending arms of the equalizers to provide an extended arc damping action; the drive tangs extending into the path of and engaging the damping springs at the hub arms.
The present invention also comprehends the provision of a vibration damper assembly wherein the equalizer arms provide an integral spring enclosure housing the opposite ends of the damper springs to prevent dislodgement of the springs and providing containment of the springs in the event of their failure. The equalizer arms also include internal spacers to separate the damper springs of adjacent spring sets. The spring spacers also serve to fix laterally the spring containment space as provided by the side plate of the equalizer arms.
The present invention further comprehends the provision of a vibration damper assembly having floating equalizers with arms that provide for the elimination of stress concentration points. The equalizer arms have generally straight or parallel sidewalls from the central portion journalled on the hub to the outer rounded arm portion providing the damper spring housing with the sidewalls terminating in peripheral flanges secured together.
The present torsional vibration damper assembly will be equally useful in a torsional coupling between axially aligned shafts, in a vehicle clutch for a manual transmission or in a lock-up clutch in combination with a hydraulic torque converter.
Further objects are to provide a construction of maximum simplicity, efficiency, economy and ease of assembly and operation, and such further objects, advantages and capabilities as will later more fully appear and are inherently possessed thereby.